Visualizing Everyone that has Ever Lived

 

How do you visualize every human that has ever lived in the last 2 million years? Max Roser with Our World in Data had the idea to turn us all into grains of sand within an hourglass, and to equate the passing of people to the passing of time. The Humanity Today and Humanity’s Past infographic highlights a few key points in history and gives us a perspective of just how population growth has exploded over the last 2000 years.

Our past

Before we look ahead, let’s look back. How many came before us? How many humans have ever lived?

It is not possible to answer this question precisely, but demographers Toshiko Kaneda and Carl Haub have tackled the question using the ​​historical knowledge that we do have.

There isn’t a particular moment in which humanity came into existence, as the transition from species to species is gradual. But if one wants to count all humans one has to make a decision about when the first humans lived. The two demographers used 200,000 years before today as this cutoff.1

The demographers estimate that in these 200,000 years about 109 billion people have lived and died.2

It is these 109 billion people we have to thank for the civilization that we live in. The languages we speak, the food we cook, the music we enjoy, the tools we use – what we know we learned from them. The houses we live in, the infrastructure we rely on, the grand achievements of architecture – much of what we see around us was built by them.

Our present

In 2022 7.95 billion of us are alive. Taken together with those who have died, about 117 billion humans have been born since the dawn of modern humankind.

This means that those of us who are alive now represent about 6.8% of all people who ever lived.

These numbers are hard to grasp. I tried to bring it into a visualization to put them into perspective.3

It’s a giant hourglass. But instead of measuring the passage of time, it measures the passage of people.

Each grain of sand here represents 10 million people: each year 140 million babies are born. So we add 14 grains of sand to the hourglass. Every year, 60 million people die; this means 6 grains pass through the hourglass and are added to the large number of people who have died.4

As noted on the graphic, this is an updated adaptation of a 2013 visualization by Oliver Uberti.

Found on Daily Infographic

Inexpensive Generic Prevents Bleeding Deaths after Childbirth

Generic drug prevents post-birth bleeding deaths

An inexpensive generic drug has been found to prevent hemorrhaging in women after childbirth.

The WOMAN Trial, involving more than 20,000 women in 21 countries, found that tranexamic acid “could save the lives of mothers who would otherwise bleed to death after childbirth,” according to the trial’s website. Tranexamic acid is an antifibrinolytic agent. It is on the WHO’s List of Essential Medicines.

In the United States, tranexamic acid is sold under the brand name Lysteda and Cyklokapron, with an indication for treating severe menstrual bleeding. The generic form of the drug costs about $2 per dose.

The study, conducted by the London School of Hygiene and Tropical Medicine, was published in the April 26 issue of The Lancet.

In the trial, death due to bleeding was reduced by about a third when tranexamic acid treatment was given within three hours. Tranexamic acid reduced the need for laparotomy to control bleeding by more than a third.

There were no side effects observed from the drug for either mothers or babies.

“We now have important evidence that the early use of tranexamic acid can save women’s lives and ensure more children grow up with a mother,” the website stated.

Postpartum hemorrhage is the leading cause of maternal death worldwide.

In the randomized, double-blind, placebo-controlled trial, researchers recruited women 16 years and older with a clinical diagnosis of postpartum hemorrhage after a vaginal birth or cesarean section from 193 hospitals in 21 countries.

They randomly assigned women to receive either 1 gram (10 mg/ mL) of IV tranexamic acid or matching placebo, in addition to usual care. If bleeding continued after 30 minutes, or stopped and restarted within 24 hours of the first dose, a second dose of 1 g of tranexamic acid or placebo could be given.

The researchers found that death due to bleeding was significantly reduced in women given tranexamic acid (155 of 10,036 patients versus 191 of 9,985 patients in the placebo group). In women given treatment within three hours of giving birth, death was reduced most significantly (89 in the tranexamic acid group versus 127 in the placebo group).

“Tranexamic acid reduces death due to bleeding in women with post-partum hemorrhage with no adverse effects,” the researchers wrote in The Lancet. “When used as a treatment for postpartum hemorrhage, tranexamic acid should be given as soon as possible after bleeding onset.”

Your Nose Knows: Even An Undetectable Smell Of Death Triggers Fight-Or-Flight Response

New research suggests that we humans, just like animals, perceive and respond to the smell of death as threatening.Erin Perry, CC by 2.0

By Susan Scutti

When animals die they release an unpleasant smell created in part by putrescine, a chemical compound resulting from the breakdown of fatty acids in the putrefying tissue of dead bodies. New research suggests that we humans, just like animals, perceive and respond to this scent as threatening.

“These are the first results to show that a specific chemical compound (putrescine) can be processed as a threat signal,” wrote Dr. Arnaud Wisman, co-author and a psychologist at the University of Kent, and Dr. Ilan Shrira, co-author and a visiting assistant professor of psychology at Arkansas Tech University. “Thus far, nearly all the evidence for threat chemosignals has come from those that are transmitted by body sweat.”

POWER OF SCENT

“We do not know why we like (or dislike) someone’s smell, and we’re usually not aware of how scent influences our emotions, preferences, and attitudes,” Wisman and Shrira told Medical Daily in an email, adding that “it is hard to think of a scent as frightening.”

However, in the animal kingdom, scent is fundamental to survival and various studies have shown that putrescine acts as a powerful chemosensory signal that triggers animals to leave or avoid an area. Humans similarly respond to obvious threats, which generally increase our vigilance and sharpen our reactions, preparing us for “fight-or-flight,” the researchers explained. Despite the popular belief that “fight” is the more common reaction to a threat, the co-authors said “flight” is actually the preferred human response in most cases. To underline their point, the researchers cited a study where people confronted by a threatening stranger chose to distance themselves and only became aggressive (and this included verbal as well as physical aggression), if the get-away option did not exist.

Considering a wide variety of past research on scents and behavior, Wisman and Shrira wondered, Would putrescine prompt threat response behaviors in humans?

And so they conducted a series of four experiments in which participants were exposed, consciously or unconsciously, to putrescine. Observing participants' behavior, the researchers compared them to participants who had been exposed to other scents. For example, in the fourth experiment, participants were primed with one of three scents — putrescine, ammonia, or water (neutral). Next, participants read about a foreign student who criticized their own value system and then they were asked to evaluate this student.

Putrescine led to greater hostility compared to the other two scents, the researchers discovered after analyzing the results. Interestingly, the ammonia group and the neutral group participants responded more or less identically. Similarly, the other three experiments revealed how even brief exposure to putrescine increased vigilance, in turn leading to fight-or-flight readiness.

“Participants in our studies were most likely not aware of the effect of putrescine on their behavior because people are not familiar with putrsescine and do not consciously associate it with death or fear,” said Wisman and Shrira, and their research supports this claim: None of the participants in the fourth experiment reported being aware of any scent.

When asked if putrescine might be considered a kind of “opposite” scent of pheromones, the researchers said, “Putrescine signals a different type of message than pheromones, but people’s responses to putrescine (avoidance and hostility) do seem indeed to be the opposite of responses to many sexual pheromones.” In either case, both putrescine and pheromones elicit a very human reaction. Apparently, sometimes our noses know more than we do.



Source: Wisman A, Shrira I. The smell of death: evidence that putrescine elicits threat management mechanisms. Frontiers in Psychology. 2015.

Microbes show up on schedule after death

MICROBIAL CLOCK  Telltale crews of microbes (including bacteria from a group called Enterobacteria, shown here) colonize the soil beneath a decomposing body during different stages of decay.

BY MEGHAN ROSEN

Dead people tell no tales — but dead people’s microbes do.

Bacteria, fungi and worms living in the soil beneath a decomposing body can help reveal the time — and place — of death, scientists report December 10 in Science.

Researchers have tracked the comings and goings of cadaver microbes before, but the new study is the mostcomprehensive survey yet. For months, microbial ecologist Jessica Metcalf of the University of Colorado Boulder and colleagues tallied up microbes on and near dead mice and humans.

As bodies decayed, similar microbes cropped up like clockwork, even on different soil types and during different seasons of the year, the team found. The microbes were so predictable that researchers could estimate the time of death (within a few days) of a body that had been dead for about a month.

And because telltale microbes stayed in the soil long after a body had been moved, they could offer investigators clues about potential crime scenes, the team suggests.